1. Division of Gastroenterology and Hepatology; Department of Internal Medicine; School of Medicine; Keio University; Tokyo Japan
2. Center for Diagnostic and Therapeutic Endoscopy; School of Medicine; Keio University; Tokyo Japan
3. Center for Advanced IBD Research and Treatment; Kitasato University Kitasato Institute Hospital; Tokyo Japan
4. Center for Preventive Medicine; School of Medicine; Keio University; Tokyo Japan